Liquefied hydrocarbon gas storage and dispensing system



July 18, 1939. D. J. LITTLE 2,166,914

LIQUEFIED HYDROCARBON GAS STORAGE AND DISPENSING SYSTEM Original FiledMay 28, 1937 2 Sheets-Sheet 1 D. J. LITTLE 2,166,914 LIQUEFIEDHYDROCARBON GAS STORAGE AND DISPENS ING SYSTEM July 18, 1939.

OriginalFiled May 28, 1937 2 Sheets-Sheet 2 Patented July 18, 1939UNITED STATES PATENT OFFICE David J. Little, San Antonio, Tex.,assignorto Southern Steel Company, a corporation of Texas ApplicationMay 28, 1937, Serial No. 145,390 Renewed March 22, 1939 11 Claims.

This invention relates to liquefied gas storage and dispensing systemsand, among other objects, aims to provide certain improvements in thesystem disclosed in my application Ser. No.

136,489, filed April 12, 1937. The main idea is to provide an improvedgas generator comprising awater tank or container in which the water ismaintained at a substantially constant temperature and through which theliquefied gas is discharged to be cleansed and the gas entrains a smallamount of water vapor. Also, the idea is to use the heated water torevaporize any condensate in the gas service main.

'w Other aims and advantages of the invention will appear in thespecification, when considered in connection with the accompanyingdrawings, wherein:

Fig. 1 is a side elevation of a system embodying the invention;

Fig. 2 is an enlarged sectional view of the gasifler or generator shownin Fig. 1, parts being shown in elevation;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is a fragmentary sectional view on a furv ther enlarged scale ofa water heater shown in Fig. 2;and

Fig. 5 is a sectional View taken on the line 5-5 of Fig. 2.

Referring particularly to the drawings, the sys tem shown forillustrative purposes is adapted to generate gas for domestic andcommercial usefrom volatile constituents of petroleum or mixtures ofliquefied hydrocarbon gases, such as butane, iso-butan'e, etc. In thisinstance. a pressure storage tank In is shown as being buried in theground below the frost line in heat exchanging relation with thesurrounding earth fill. This tank is-adapted to be. partially filledwith the liquefied gas and is shown as having a protecting casing llprojecting upwardly above the ground level. A valved gas vent pipe I!and a combined valved filling and gauge pipe l3 are connected to the topof the tank and project into the casing so 45 that the pipes may beconnected to a service truck tank when the storage tank is to be filled,it being understood that the displaced gas in the tank will dischargethrough the pipe l2 into the gas space of the service truck tank. Thelevel of the 50 liquefied gas in the storage tank will be indicated byan ordinary gauge it which is operated by a float IS in the tank. Thevent pipe projects downwardly into the storage tank' to approximatelythe desired maximum level of the lique- 55 fied gas so that the tankcannot be overfilled.

It will be understood that some of the highly volatile constituents ofthe liquefied gas in the storage tank will be vaporized in the tank dueto the exchange of heat with the surrounding earth fill and therebymaintain a pressure in the tank. 5 In this example, the pressure of thegas above the liquid level in the storage tank is utilized to dischargeliquefied gas and deliver it to the gas generator or gasifier. Herein, adischarge pipe It extends approximately to the bottom of the stor- 10age tank and upwardly through the lower portion of the casing I I whereit is provided with a cutoff valve II. It is shown as being buried inthe ground at a substantial depth and is connected to discharge into thebottom portion of a vertical vIii stand pipe or water tank l8 which ispartially filled with water through a plugged filling opening at thetop, the arrangement being such that the liquefied gas vaporizes bybeing heated in the tank and bubbles up through the water. A cut oilvalve l9 and a check valve 20 are provided in the pipe [6 near theground level. The check valve prevents water in the tank l8 fromdraining into the storage .tank.

The gas is generated in the water tank ll which is indirectly heated toa constant temperature and discharges from the top of the tank through avalved pipe 2| and the usual pressure regulator orreducing valve 22 to agas main 23 shown, as being buried in the ground at approxi- '30 matelythe same level as the bottom of the water tank l8. An excess pressurerelief valve 24 is provided in the pipe line 2i and a vent pipe 25 isconnected to the pressure regulator or pressure reducing valve 22.

In this instance, a portion of the generated gas I is used to heat thewater in the tank It. For this purpose, there is shown a fiue type waterheater 26 having a vertical flue 2! and a conduit 28 extending into thetank l8 for circulating the heated water and exchanging heat with thewater in the tank. The heater is separated from the tank to avoid dangerof an explosion. A branch pipe 29 is connected to the gas main 23 tosupply gas through a valved gas pipe 30 to a small burner 3| at thebottom of the water heater 26. The burner is shown as being controlledautomatically by a thermostat 32 extending into the water tank l8 andarranged to operate a valve 33 in the burner supply pipe 30. Thearrangement is such that the heatermaintains the temperature of thewater in the tank l8 substantially constant. It is to be understood,however, that other well known thermally controlled valves may a beemployed for this purpose. The water heater is adapted to be filled orpartially filled with water through a filling opening closed by afilling plug 34. 4 To prevent the heater from exploding due to excessivepressure in case the thermostatic valve does not function properly,there is shown a fusible plug in the top which is adapted to melt at,say, 212 and permit some of the water or steam to escape from theheater. The heater is shown as being protected by a conical hood 36removably secured to its upper end. The arrangement is such that anywater or steam which may be discharged through the fusible plug openingwill be deflected by the hood and some of it will fall through the fiue21 on the burner 3| and extinguish the flame.

In cold climates or during extremely cold weather, some of the gas inthe service main 23 will condense and cause considerable trouble if itis not revaporized. In this example, any condensate formed in theservice main is revaporized by the heated water in the tank I8.Referring to Figs. 2 and 3, the branch 29 is connected to the lowestpart of the service main and extends into the bottom portion of the tankl8, having a closed end 31 within the tank. Any condensate in the mainwill drain back into the closed pipe and be revaporized by heat absorbedfrom the water.

From the foregoing description. it will be seen that the improved systemis entirely automatic and reliable in operation. The indirect orexternal heater maintains the temperature of the water in the tank orgas generator substantially uniform and the gas at a substantiallyconstant pressure. The gas is cleansed oi tarry products by the waterand is humidified to improve its combustion quality. Moreover, theindirect heater which may be arranged inside a cellar or house avoidsany danger ofan explosion which might be caused by a direct heater." Thegenerator also revaporizes all condensate in the gas main and therebyprevents any stoppage of gas fiow due to trapped condensate. Theindirect heater and generator may be assembled at the factory andinstalled as a unit. Furthermore, the whole system can be sold at a veryreasonable cost and is especially adapted for household and commercialuses, even in the coldest climates.

What is claimed is:

1. In a liquefied gas storage and dispensing system having anunderground pressure storage tank and a dispensing pipe for theliquefied gas, a gas generating unit including a container partiallyfilled with water to which the dispensing pipe is connected below thewater level; and a heater having indirect heating means connected toheat the water in said container.

2. In a liquefied gas storage and dispensing system having anunderground pressure storage tank and a dispensing pipe for theliquefied gas, a gas generating unit including a container par-. tiallyfilled with water to which the dispensing pipe is conected below thewater level; a heater having indirect heating means connected to heatthe waterin said container; and thermally controlled means connected tomaintain the temperature of the water substantially constant.

3. In a liquefied gas storage and dispensing system having anunderground pressure storage tank and a dispensing pipe for theliquefied gas. a gas generating unit including a container partiallyfilled with water to. which the dispensing pipe is connected below thewater level; a heater for said container; and a thermostat responsive tothe temperature in the container connected to control the heater andthereby maintain the temperature of the water substantially constant. 4.In a liquefied gas storage and dispensing system having an undergroundpressure storage tank and a dispensing pipe for the liquefied gas, a gasgenerating unit including a container partially filled with water towhich the dispensing pipeis connected below the water level; a gasconduit connected to said container above the water level; ,a pressureregulator connected to said conduit; and an indirect heater for saidcontainer supplied with gas from said conduit.

5. In a liquefied gas storage and dispensing system having anunderground pressure storage tank and a dispensing pipe for theliquefied gas, a gas generating unit including a container partiallyfilled with water to which the dispensing pipe is connected below thewater level; a gas conduit connected to said container above the waterlevel; a pressure regulator connected to said conduit; a separate waterheater connected to heat the water in said container; a burner for saidheater supplied with gas from said conduit; and a thermostatic valvecontrolling said burner responsive to the temperature of the water insaid container to maintain the temperature of the water substantiallyconstant.

6. In a liquefied gas storage and dispensing system having anunderground pressure storage tank and a dispensing pipe for theliquefied gas, a gas generator comprising an upright tank partiallyfilled with water to which said dispensing pipe is connected. near thebottom so that the liquefied gas delivered thereto passes through thewater; a check valve in said dispensing pipe to prevent water fromfiowing into said storage tank; a gas delivery conduit connected to theupper portion of said water tank and having a pressure reducing valvetherein; and an indirect heater for the water in said tank having a gasburner connected to be supplied with gas delivered therefrom.

7. In a liquefied gas storage and dispensing system having anunderground pressure storage tank and a dispensing pipe for theliquefied gas, a gas generator comprising an upright tank extendingabove the ground level and partially filled with water to which saiddispensing pipe is connected below the water level; a check valve insaid dispensing pipe to prevent water from fiowing into the storagetank; a gas delivery conduit connected to'the upper end of said gasgenerating tank; a pressure regulating valve in said conduit; a gas mainhaving its lowest portion adjacent to the lower end of said gasgenerating tank; a heatertor the water in said gas generating tanksupplied with gas from said conduit; a thermostatically controlled valvefor the heater connected to maintain the temperature of the water insaid gas generating tank substantially constant; and a pipe connected tosaid gas main at its lowest point extending into the lower portion ofsaid gas generating tank to absorb heat from the water therein andrevaporize any condensate formed in saidgas main.

8. In a liquefied gas storage and dispensing system having anunderground pressure storage tank and a dispensing pipe for theliquefied gas, 'a gas generating unit comprising a container partiallyfilled with water to which said dispensing pipe is connected below thewater level; heating means connected to said container; a gas deliveryconduit connected to said container and having its lowest point near thebottom of said container; and a pipe connected to said gas deliveryconduit extending into said container in heat exchanging relation withthe water therein to revaporize any condensate formed in said container.

9. In a liquefied gas storage and dispensing system having anunderground pressure storage tank and a dispensing pipe for theliquefied gas, a gas generating, unit comprising an upright tankpartially filled with water to which said dispensing pipe. is connectedbelow the water level; a gas delivery conduit connected to the upper endof said tank; an indirect heater for the water in said tank including awater container and a gas burner connected to be supplied with gasgenerated in said tank; and a fusible plug in said heater to preventoverheating of the water therein.

10. In a liquefied gas dispensing system having a pressure storage tankand filling appurtenances connected thereto whereby it may be partiallyfilled while the pressure is maintained therein; a separate gasgenerating tank partially. filled with liquid; a liquid eduction pipeconnected to deliver gas in the liquid phase from the storage tank tothe generating tank below the liquid level therein; valve means in saideduction pipe; a gas service pipe connected to the vapor space in saidgenerating tank; and a pressure reducing regulator connected to saidservice pipe, one of said tanks being buried in the ground to absorbheat from the surrounding earth.

11. In a liquefied gas dispensing system having a pressure storage tankand filling appurtenances connected thereto whereby it may be partiallyfilled while the pressure is maintained therein, a separate gasgenerating tank partially filled with liquid; a liquid eduction pipeconnected to deliver gas in the liquid phase from the storage tank tothe generating tank below the liquid level therein; and an undergroundgas service pipe having a condensate trap portion at its lowest pointarranged in heat exchanging relation with the generating tank.

DAVID J. LITTLE.

